Duplex double-acting steam pump



Nov. 25, 1952 F. J. DAVIDSON DUPLEX DOUBLE-ACTING STEAM PUMP 7 Sheets-Sheet 1 Filed April 20, 1948 ATTORNEY Nov. 25, 1952 F. J. DAVIDSON DUPLEX DOUBLE-ACTING STEAM PUMP 7 Sheets-Sheet 2 Filed April 20, 1948 Imam/tow /4 TTOR/VEY Nov. 25, 1952 F. J. DAVIDSON DUPLEX DOUBLE-ACTING STEAM PUMP 7 Sheets-Sheet 3 Filed April 20, 1948 KTQ@ MM /TTR/VEY Nov. 25, 1952 F. J. DAVIDSON DUPLEX DOUBLE-ACTING STEAM PUMP 7 Sheets-Sheet 4 Filed April 20, 1948 M MW A TTQ/P/VEY @ZM/Ww Nov. 25, 1952 F. J. DAVIDSON DUPLEX DOUBLE-ACTING STEAM PUMP 7 Sheets-Sheet 5 Filed April 2o, 194e W m n\\ @Ima ewa M I |.r mw d L f TA M kw ww im A m Wb fm k. Jl,\ N m, m Q S ws N i\ Q) S) NN) lm \.\L\ NNTII s i@ 7 mQ mf im l l M Il n @s .I LII! .I I Il @u /MM 7 M//J/ Nn f W .bm h. A Im Nov. 25, 1952 F. J. DAVIDSON DUPLEX'DOUBLE-ACTINGv STEAM PUMP '7 Sheets-Sheet 6 Filed April 20, 1948 Nov. 25, 1952 F. J. DAVIDSON DUPLEX DOUBLE-ACTING STEAM PUMP 7 Sheets-Sheet '7 Filed April 20, 1948 R m m V m m m V M d M m kmv wu SSR v6 i WW w/ Patented Nov. 25, 1952 UNITED STATES PATENT OFFICE DUPLEX DOUBLE-ACTING STEAM PUMP Frank J. Davidson, Philadelphia, Pa.

Application April 20, 1948, Serial No. 22,036

(Cl. 10S-49) 7 Claims.

This invention relates to duplex double action pumps such as used for boiler feed pumps, as an illustration, and wherein reciprocating pistons operate in parallel cylinders, and in particular the invention includes a pump having two parallel cylinders with auxiliary reciprocating cylinders forming pistons therein and with stationary pistons providing combination intake and exhaust valves positioned in the auxiliary cylinders and connected with tubular piston rods to opposite ends of the pump housing. The housing is provided with inlet and discharge connections with automatically operating valves therein and also valve operating pistons connected through the auxiliary cylinders to the valves in the stationary piston.

The purpose of this invention is to provide an improved steam driven duplex double action pump in which the valves are incorporated within the expansible chamber and operated by fluid pressure therein wherein all exterior operating parts and packing glands associated therewith are eliminated.

The usual pump of this type requires considerable maintenance as there are six glands and two iiuid pistons that require frequent repacking making it necessary to stock large supplies of costly packing. The metal piston rings wear rapidly and score cylinders requiring periodic renewal and reboring. The piston rods also score and develop shoulders, and the bearings wear and require new bushings. Due to the above and wear in other mechanically operating instrumentalities associated with pumps of this type the eiiciency is comparatively low.

With this thought in mind this invention contemplates an improved type of pump wherein the operating instrumentalities are of the iloating type wherein the expansible chamber or moving cylinder which functions as a piston floats in a guide cylinder in the uid being pumped alternately drawing uid in at one end and forcing it out of the other and with the pressure of the uid automatically tripping a slide valve within the moving cylinder as the said` cylinder approaches the end of the stroke atveach end.

The object of this invention is, therefore, to provide a double acting duplex pump wherein substantially all of the operating instrumentalities are incorporated within the pump housing and are positioned in the fluid being pumped.

Another object of the invention is to provide a double acting steam pump in which the pressure of the fluid being pumped actuates the valve mechanism to reverse the direction of the reciprocating element.

Another object of the invention is to provide a double acting steam pump in which substantially all packing glands are eliminated.

A further object of the invention is to provide a duplex double acting steam pump wherein substantially all of the operating instrumentalities are incorporated within the housing and positioned in the fluid being pumped which is of a simple and economical construction.

With these and other objects and advantages in view the invention embodies a unitary housing having two parallel cylinders therein with auxiliary floating cylinders in the parallel cylinders and stationary pistons with tubular connecting rods in the iioating cylinders, and wherein the pistons include slide valves actuated by fluid pressure through small pistons in cylinders .at the end of the housing.

Other features and advantages of the invention will appear from the following description taken in connection with the drawings, wherein:

Figure 1 is a view showing a vertical longitudinal section through the housing of the pump and on the center of one of the cylinders thereof, with parts broken away.

Figure 2 is a plan view illustrating the connections between the fluid pressure and valve operating cylinders.

Figure 3 is a view showing an end elevation of the housing looking toward the inlet and discharge end.

Figure 4 is a cross section through the housin taken on line 4-4 of Figure 1.

Figure 5 is a horizontal longitudinal section through the auxiliary or oating cylinder, with the other parts omitted.

Figure 6 is a longitudinal section through the stationary piston showing the slide valve therein, and on an enlarged scale. f

Figure 'Tis a detail showing the exhaust end of the piston.

Figure 8 is a similar detail showing the steam insert in the piston.

Figure 9 is a cross section through the stationary piston taken on line 9-9 of'Figure' 6, and showing the slide valve therein.

Figure 10 is a detail showing a sectional plan through the steam end of the pump illustrating the valve actuating piston and cylinder on an enlarged scale.

Figure 11 is a detail showing the split ring used at each end of the floating cylinder.

Fig. 12 is a section through the ring shown` in Figure 11.

Figure 13 is a longitudinal section through a 3 check valve adapted to be used in the connections to the valve actuating cylinder.

Figure 14 is a sectional plan through the valve shown in Figure 13.

Figure 15 is a diagrammatic view illustrating the operation of the pump.

Referring now to the drawings wherein like reference characters denote corersponding parts the duplex double acting pump of this invention includes a `housing Ill 'having an inlet connection II and an outlet or discharge connection I2, with stationary guide cylinders I3 and I4 in the housing, floating cylinders I5 and I5 -in the guide cylinders, stationary pistons I1 and I3 in the floating cylinders, and valve actuating pistons I9 and 20 in cylinders 2| and 22, respectively,.at the end of the housing.

In the design shown the housing I is :provided with supports 23 and 24`with openings 25 and 26 :ln the`upper'surface,:andthe opening 25 is pro- "v'ided withafcover plate 21, with .a similar cover plate 28 on the 'opening.26.. The fsideswarefalso provided-with -hand holes 29 andSD having cover fplates'IB-I rand -32fthereon respectively, and inthe f-lowergpart isa Vboss -33.having a ange `34 -to which Athe-intakeconnection II is secured by bolts 35, :Whle'inthe upper part-of the same end is a -boss 36 having a flange -31'to-which the -discharge con- .;nectionis-secured -bybolts f38. y l

'Ihegu-ide cylinders I3 and I4 a-re held vin a .centrallyfdisposed web 39 that divides the .housing .into chambers 4U and. 4I, .and in the 'lower -partof the housing is a horizontally disposed partition v42 :having openings 4,'43 therein which :provides alowerlow .pressure lfluid chamber 44, `while-'the upper part-is another horizontally disposed partition 45 having openings 46 therein thatprovidesan upper high pressure 'fluid chamberm.

The .openings 43 lin -thepart'ition 42 are provided vvith rings 48 providing valvejseats and valves 49 with stems 50 seat on the rings with 'thestem's slidablyheldinguidesI and with the valves resiliently held against the Vseats Vby springs 52. The openings 48 in the'partition 45 are provided with `rings 53 that provide valve seats 'and valves 54 with lstems A55 Aare positioned on the seats with the stems held in guides 56 a'n'dwith"the 'valvesheld by springs 51.

The floatingcylinders and stationary pistons of the guide cylinders I3 and I4 are similar and the-same reference `numerals are applied to both. The oating cylinders I and `I'I are preferably made ol? 'bronze with 'steel liners '58,.and the ends `lof 'the 'cylinders 'are formed with annular 'flanges 59 and 69 and recessesl fand 62 4are provided 'behind Lthe flanges. `.The kexhaust `end of each hoatingpylinder isprovi'd'ed with a lhe'add63 having an annular flange-94 corresponding with the :flange 159 vrand secured thereto by 'a split `ring formed in two sections 65 and 66 with fannular recesses 161 :and 68 in .the inner surfaces thereof that t snugly over the flanges ton'the -ends of the-'cylinder .and-flanges 'of the cylinder heads. "With thefsplit rings Afreely slida-ble in the guide or stationary cylinders VI3 and 14 :the cylinder :headswill Vbe locked in the endsof "the cylinders.

Ihe-split rings are vprovided with dove-tail interwith a head 15 similar to the head 63 and this head is formed With an annular flange 16 that is secured to the flange 60 by a split ring similar to the ring at the other end. The head 15 is provided with a centrally disposed bore 11 through which it is slidably positioned on a tubular connecting rod 18 and the bore is formed with a packing gland 19 having a nut 80 therein. The ange ,18 is also provided with openings 83 and `llthrough which rods 85 andSS Aextend that connect a slide valve 31 in the piston I'I to a piston I9 in the auxiliary cylinder 2|. The openings 83 and 84 -are provided with packing glands 89 and '98 with nuts 9| and 92 in the ends thereof :for-holding the packing.

vEach side of .thehousing is provided with openings 93 'and 94 which are aligned with the cylindersand the opening 93 is closed by a iiange 95 while the opening 94 is closed by a ange 96 `on which .the cylinder .2| in which the piston l.I5 is located is mounted by Ybolts 91. The outer .end o'f the connectingrrod 18 vis Apositioned fin .a socket 49B in a boss 9S on the inner surface of the flange 95 and a key |09 is provided to prevent the rod turning. vThe socket 98 communicates with a steam supply pipe IGI through a passage |62, as shown in Figure .1. The outer end of the connecting rod 12 is threaded through the flange 95 with a bushing |03 threaded in the flange and provided Ywith a nut |94 having openings fora spanner wrench by .whichthebushing .may bje tui-ned. A lock 'nut |95 .is provided on 'the rod `inside ofthe flange and an exhaust pipe vvlfll' ism'ounted on the flange .through an elbow |91 and a'flange |98.

On the inner end of the connecting rod 18 is-a core |99 having .outlet openings 'IIll and III therein communicating with the interior of the lrod'18, and positioned Ato 'register with passages |Il2 and I'I'3in `the piston I1. The core v|09 is also provided .with 'inlet ,openings |I.4 and |I5 that communicate 'with the interior of the connecting rod 12 through a .passage I|i Vand these openings are positioned to register with exhaust openings II`1 and HS in the piston. The rod 18 .is also-provided'with 'a flange I I9 that ts snugly againstvthe end ofthe piston andthe flange is vprovided with an opening |20 registering Vwith the passage `I I3 and 'anopening I2'I that registers Vwith thepassage I I8.

`The slide valve 81 is provided-With a port |22 that is positioned to register with the openings AII 'I .and IIB alternately and this valve is actuated by 'the pistonI9 'to which it is connected by the rods 85 and :86. The ends of the rods ,85 and 86 Vareformedwith shoulders |23 with studs |24 extendinglfrom the shoulders and provided with ,nuts '|25 and. |26 that secure the ends of the rods yin the web |21 of the piston. The piston is provided 'with a sleeve |28 having inwardly extending edges as showninFigure .1.

'The ,endof thepiston I1 is provided with locating recessesl that `are Apositioned to receive VVpins-82 on theinner surface of the flange H9,

as shown in Figure 5, to maintain the ,ports `in the piston in operative positions.

The ,pistons I9 and 29 are actuated by fluid Vpressure andas the pressure builds up in Athe .chambers 4.9 and 4I ,the pistons move-to operate the slide valve 81 in thefstationary piston.

The V'fluid pressure is vprovided through a series of small connections with a connection|30 having a .check valve I3| 'therein extending from a point v|32 in the chamber 4I at thesteam end of `the cylinder I4 to the point |35 .in Vtheuendf-of cylinder 2|, a connection |34 having a check valve |36 therein extending from the chamber 40 in the opposite end of cylinder I4 to a point I33'in the outer end of the cylinder 2| and connected to the housing at the point |31, a connection |38 with a check valve |39 therein from the point I 40 in the chamber 40 of the exhaust end of the cylinder I3 to the point |45 at the inner end of the cylinder 22, and a connection |42 with a check valve |43 therein from the point |44 in the chamber 4I in the steam end of the cylinder I3 to the point I4I in the other end of the cylinder 22.

As the oating cylinder I5 travels toward the exhaust end of the housing from the position shown in Figure 1, pressure builds up in the chamber 40 whereby the uid passes through the connection |38 to the inner end of the cylinder 22 and the piston actuates the slide valve to open the passage |I3 to the steam supply and at the same time opens the passage II1 to the exhaust. This causes the oating cylinder I6 to start moving toward the exhaust end of the pump, and as the pressure builds up in the chamber 43 of the cylinder I4 the uid passes through the connection |34 to the other side of the piston I9 so that the slide valve in the piston I1 is moved in the opposite direction, and by proper timing and synchronization the cylinders will reciprocate continuously with one following the other.

The check Valves used in the small control connections are shown in Figures 13 and 14, and it will be understood that any suitable check valve with a control or a diaphragm valve may be used.

The valves shown are formed with a housing |50 having a horizontally disposed web I5I with a valve seat |52 therein, and a valve ring |53 on a oating sleeve |54 is controlled by an adjusting valve |55 carried by a threaded stem |56 in a bushing |51 and held in adjusted position by a lock nut |58 covered by a cap |59. The valve body is provided with an inlet connection |60 and an outlet connection I 6I, and below the Valve |53 is an annular recess |62 with openings I 63 extending downward therefrom. As the demand increases the tendency is to close down the check valves to permit longer stroke before the cutoff or reversing action, and as the demand decreases the Valve raises to shorten the stroke, thereby l pumping less water or iluid.

With the pump at rest the needle check valve |36 is opened whereby pressure :from the chamber 40, passing through the connection |38 and entering the cylinder 22 at the point |45 moves the piston toward the opposite end of the cylinder whereby the valve sleeve 81 is moved by the piston to open steam port II!) through which steam passes through opening I I2 into the floating cylinder I'6 which builds up pressure in chamber 40. This pressure passes through connection |34 to the outer side of cylinder 2 I, forcing piston I9 inwardly and moving valve sleeve 81 in cylinder I5 so that steam is supplied to the end of iioating cylinder I5, forcing cylinder I5 from the position shown in full lines in Figure 15 to that shown in dotted lines.

This builds up pressure in chamber 4I which passes through the connection |42 to the outer end of the cylinder 22 and drives the piston 20 inwardly carrying the valve sleeve 81 into the piston I1 whereby steam is admitted to the end of the cylinder I6 which drives the cylinder from the position shown in dotted lines in Figure 15, to that shown in full lines. By this means pressure builds up in chamber 4I and passes through connection |30 to the inner end of the cylinder 2| driving the piston I9 outwardly and drawing the Valve sleeve 81 in the stationary piston so that steam is admitted to the end of the floating cylinder whereby the cylinder travels from the position shown in dotted lines in Figure 15, 'to that shown in full lines.

This action builds up pressure again in the chamber 40 and fluid under pressure is again carried through the connection |38 to the inner end of the cylinder 22, and the cycle of operation is repeated.

It will be understood that other changes may be made in the design and arrangement of the parts without departing from the spirit of the invention.

What is claimed is:

1. A duplex double acting pump of the reciprocating type comprising a housing having a pair of stationary cylinders therein, a stationary pis- Jcon in each of said cylinders, tubular intake and exhaust piston rods extending from opposite ends of said pistons, floating cylinders providing movable pistons slidably mounted on the stationary pistons and rods and slidable in the cylinders. slide valves in the stationary pistons opening the inner ends of the oating cylinders alternately to the intake and exhaust rods, and means actuating the said slide valves by the pressure of uid in the pump, said housing having intake and discharge connections.

2. A double acting reciprocating pump comprising a substantially enclosed housing having a pair of stationary cylinders therein, a stationary piston in each of said cylinders, tubular intake and exhaust piston rods extending from opposite ends of the cylinders and connected to the pistons, floating cylinders providing pistons slidably mounted on the pistons and rods and slidable in the cylinders, slide valves in the stationary pistons opening the inner ends of the iioating cylinders alternately to the intake and exhaust rods, and means actuating the said slide valves by fluid pressure of the pump, said housing having intake and discharge connections.

3. A double acting reciprocating pump comprising an enclosed housing with parallel stationary cylinders therein and having intake and discharge connections and a dividing transverse partition, check valves in the said intake and discharge connections, stationary pistons with tubular connecting rods extending from the ends thereof positioned in the cylinders, oating cylinders slidably mounted over the stationary pistons with the ends thereof slidable on the said tubular connecting rods and with the cylinders slidable in the stationary cylinders and providing pump pistons, means supplying steam to the connecting rods at one end of the housing, means exhausting the steam through the connecting rods at the opposite end of the housing, and means controlling the passage of the steam and exhaust in the stationary pistons.

4. A duplex reciprocating pump comprising a housing having parallel stationary cylinders therein with the cylinders supported at the center in a dividing transverse web, said housing having high and low pressure chambers with an outlet connection from the high pressure chamber and an inlet connection to the low pressure chamber, valves between the high and low pressure chambers and inner chambers in which the stationary cylinders are positioned, oating cylinders slidably mounted in said stationary cylinders providrame-,oss

fing fpistons,*rstationary ipi'stons `in said oating Acylinders'havingltubular rods extending-from the ends vthereof vthrough theends of the oating cylindersandsecured in the .ends of thehousing,

slide valvesin the .stationary pistonsand means actuating .the 4slide .valvesf by the fluid pressure .of 'the pump ,tohadmit steam alternately .to the inner ends of the oating cylinders and at the same time open the opposite ends :ofisai'd oating 'cylinders to the exhaust.

.5. A:pump as .described in-claim 14, in which theslide valve yactuating means includes pistons in auxiliary cylinders and connected to the Vsaid slide valves.

f6. `.Azpumpas describedinclaim 4,.in which the slide Valve'actuating means includes pistons in auxiliary cylinders and connected to the said'slide valves by rods extending through the ends of the l fioatingfcyllinders.

Y7. V'A pump as described .in claim 4, in which REFERENCES CITED The following references are of record inthe file of this patent:

UNITED STATES PATENTS Number Name Date V68,721 Fairclough Sept. 10, 1867 68,863 yEverett Sept. 17, 1867 2,169,703 Mason Aug. 15, 19.39 

